Deep vein thrombosis
Blood clots may form in the legs (deep vein thrombosis) during long plane flights, chiefly because of prolonged immobility. The longer the flight, the greater the risk. The risk is greatest for flights longer than 8-10 hours. Blood clots can also form after long train or car rides. Though most blood clots are reabsorbed uneventfully, some may dislodge and travel through the blood vessels to the lungs, where they may obstruct blood flow and cause life-threatening complications.
Risk factors for deep vein thrombosis include
- previous history of deep vein thrombosis
- chronic swelling of the legs or feet
- varicose veins
- use of estrogen or raloxifene (Evista)
- advanced age
- recent hospitalization or surgery
To prevent the development of blood clots on long plane flights, the following measures are recommended:
- Wear comfortable, loose-fitting clothing.
- Do not place hand luggage where it may limit leg movement.
- Walk about the cabin at regular intervals.
- Perform isometric compressions of the leg muscles (i.e. contract the leg muscles periodically while sitting).
- Avoid crosssing your legs.
- Drink plenty of fluids.
- Avoid alcohol and tobacco.
- For those with any of the above risk factors, wear compression stockings, which can be purchased in most drug stores.
Low molecular weight heparin may be considered for those at particularly high risk for thrombosis.
The chief symptom of deep vein thrombosis is swelling of the foot, ankle, or calf on one side, sometimes accompanied by pain. When the blood clot travels to the lungs, the chief symptoms are chest pain and difficulty breathing. Travelers with any of these symptoms should immediately seek medical attention.
From the World Health Organization (WHO)
Travel by air: health considerations
From the Centers for Disease Control (CDC)
Deep Vein Thrombosis/Pulmonary Embolism
From the National Travel Health Network and Centre (U.K.)
Travel Related Deep Vein Thrombosis
Compression Stockings and the Prevention of Travel Related Deep Vein Thrombosis (DVT)
From "Health Information for Overseas Travel" (U.K.)
Medical considerations for the journey: travel by air, sea or land
From the New England Journal of Medicine
Lapostalle F, Surget V, Borron SW, et al. Severe pulmonary embolism associated with air travel. N Engl J Med 2001: 345:779-83.
From Cheap Flights
Travel Tips: Travel Sickness / DVT